Estimation of interval velocity and attenuation anisotropy from reflection data at Coronation Field

Abstract

Attenuation can be extremely valuable in characterizing gas accumulations in shales and sandstones. Laboratory studies clearly indicate that attenuation is closely related to fluid saturation and mobility. Well-log analysis shows that P-wave attenuation is higher in gas-bearing rocks than in those saturated with oil or water. Extremely low P-wave quality factors (Q), ranging between 5 and 10, have been observed in some gas reservoirs. For example, such low Q values in gas sands are reported by Mavko and Dvorkin (2005) in well logs from the Gulf Coast.